Genetics or environment: which of the two has a greater influence on children’s eating behaviours?
A study by the Instituto de Saúde Pública da Universidade do Porto (ISPUP) concluded that although genetics strongly influence children’s eating behaviours, at the age of 10, their environment can greatly shape their appetite predisposition. The authors highlight the importance of implementing public health interventions related to better eating practices at an early age, given that, during this period, the youngest are more permeable to the influence of their surrounding environment.
The study, entitled Genetic and environmental contributions to variations on appetitive traits at 10 years of age: a twin study within the Generation XXI birth cohort, involved 86 pairs of twins participating in the Generation XXI cohort – an ISPUP longitudinal study that has, since 2005, followed a set of participants born in public maternity hospitals of the Metropolitan Area of Porto – with the aim of understanding how genetics and environment explain the variability of children’s eating behaviours.
According to Sarah Warkentin, first author of the article, coordinated by ISPUP researcher Andreia Oliveira, leader of the Eating Behaviours and Childhood Obesity lab of the Laboratory for Integrative and Translational Research in Population Health (ITR), “we decided to go ahead with this research because we know, through studies carried out with twins in the United Kingdom, that genetics have an important weight in explaining the different eating behaviours of children and that this influence seems to increase with age”.
“In Portugal, there were no studies to date that explained what contribution genetics and environment make to the variation in children’s eating behaviours. Therefore, we wanted to analyse this relationship in a sample of Portuguese school-age twins.”
The study analysed the eating behaviours of 86 pairs of twins, aged 10 years old, through a questionnaire completed by their parents.
Eight eating-related behaviours were assessed: food enjoyment, response to food, desire to drink, emotional overeating (when more food is eaten due to negative emotions), satiety responsiveness (for example, leaving food on the plate), slowness in eating, food fussiness (when one is very selective about what they eat) and emotional undereating (when less food is eaten due to negative emotions).
At this age, genetics were found to have an important influence on all the eating behaviours studied, influencing behaviours such as food enjoyment, desire for drinks, emotional overeating, and satiety responsiveness. The exception was emotional undereating, which appears to be a behaviour that is more influenced by the environment.
Sarah Warkentin explains that “although children’s eating behaviours are very much influenced by genetics, their environment can nevertheless shape their appetite predisposition. So, even if a child has a genetic predisposition to eat more food in response to negative emotional states or to overeat, if their environment promotes healthier eating, they can still have an appropriate weight despite their genetic predisposition to be overweight, for example” she explains.
The researchers highlight the beginning of life as the ideal moment to shape the genetic predisposition of children regarding appetite, which stems from the fact that, later on, with the increase of the child’s autonomy, genetics will acquire a greater weight and the surrounding environment will have lesser importance, making it more difficult to change inadequate eating behaviours.
What can be done? “At the beginning of life, it would be important to bet on interventions that work the family as a whole”, indicates the ISPUP researcher. “Increasing the availability of healthy foods at home and using strategies like constant exposure to fruit and vegetables, could, for example, help the child be less selective about what they eat. In addition, parents should set an example by practising healthy eating.
Outside the family environment, schools can also contribute by providing a health-promoting environment and teaching students about proper eating practices. “All this can shape the genetic predisposition of children when it comes to a greater demand for food”, she says.
In short, although there is a genetic predisposition for certain eating behaviours, it is possible to change inappropriate behaviours that promote excess weight and obesity by modifying the child’s environment from an early age.
This research, published in the journal Eating and Weight Disorders – Studies on Anorexia, Bulimia and Obesity, is also signed by researchers Milton Severo (ISPUP), Alison Fildes (University of Leeds) and Andreia Oliveira (ISPUP).
The study was funded by FEDER, from the Operational Programme Competitiveness Factors – COMPETE and the national funding from the Foundation for Science and Technology – FCT (Ministry of Education and Science of Portugal), under the projects “Appetite regulation and obesity in childhood: a comprehensive approach towards understanding genetic and behavioural influences” (POCI-01-0145-FEDER-030334; PTDC/SAUEPI/30334/2017) and “Appetite and adiposity-evidence for gene-environment interplay in children” (IF/01350/2015).